PLATE LXXYI. 
Prothyris planulata. 
Page 4(30. 
See Plate 94. 
Fig. 1. The left side of a specimen enlarged to two diameters. 
Hamilton group. Outlet of Crooked lake, N. Y. 
Prothyris lanceolata. 
Page 460. 
Figs. 2-8. A series of specimens showing the prevailing forms in this species. Fig. 8 is enlarged to two 
diameters. 
Hamilton group. Eastern and central New York. 
MoDIELLA PYGMjEA. 
Page 514. 
Figs. 9-20. A series of valves illustrating the principal varieties of form and surface characters of this 
species. Figures enlarged to two diameters. 
Hamilton group. Central New York. 
Tellinopsis subemarginata. 
Page 464. 
Figs. 21-81. A series of valves showing variations in size and form. 
Hamilton group. Eastern and central New York. 
